My simulation is about venturi scrubber. A venturi scrubber is designed to effectively use the energy from the inlet gas stream to atomize the liquid being used to scrub the gas stream, so the gas stream will more clean. The end of the inlet water pipe there is some small nozzles. This venturi have 2 inlet and 2 outlet. Two inlet are inlet water and inlet gas. Because flow in venturi scrubber is turbulent, I make inflation in region near the venturi scrubber wall. The boundary conditions are inlet water=velocity inlet, inlet gas=velocity inlet, outlet1 and outlet2 = pressure outlet. In Fluent, I use models: Multiphase VOF, Energy Equation, and Viscous is k-epsilon. Multiphase have 2 eulerian phase, that is air and water liquid. The solution method is PISO. The absolute criteria of convergence is 1e-4 except energy (energy is 1e-6). After 7903 iteration, the simulation still not convergen. The simulation also have reversed flow in outlet1 and outlet2. Anyone can help me to solve this problem?? Is the multiphase VOF true for this problem?? Any help is highly appreciated. Thanks.